The major objective is to help clarify the roles of metabolic enzymes ("converting" and inactivating enzymes) in limiting or modifying the pathophysiologic actions of kinins and angiotensins. This objective will be approached in four general ways: 1. Using intrinsically labelled polypeptides (e.g., (3H)Pro7-bradykinin, (3H)Pro4-kallidin 10, (3H)Tyr4-angiotensin II and (3H)Leu10-angiotensin I), we will examine for the occurrence of inactivating and "converting" enzymes other than angiotensin converting enzyme (kininase II). 2. We will examine pulmonary endothelial cells in culture for their ability to synthesize kininase II or to provide receptors for enzyme synthesized elsewhere. 3. We will examine the distribution and fate of BPP9alpha (SQ 20, 881), an inhibitor of kininase II which is used clinically to treat renin-related hypertension. At present, nothing is known of which factors limit the duration of action of BPP9alpha. 4. We will purify and characterize the kininase II-like activity recently discovered in urine, and we will purify and characterize the kininase II inhibitor that occurs in urine. In addition, we will examine for systematic changes in the excretion of both the enzyme and its inhibitor. Success in these studies should improve understanding of how kininase, angiotensinase and related "converting" enzymes regulate the activities of the renin-angiotensin and kallikrein-kinin systems.